This invention relates generally to transmitters, and more particularly to sonobuoy transmitters in which a phase-locked loop is modulated in order to transmit acoustic data with multichannel programmability.
Prior art approaches to sonobuoy technology have generally been limited to fixed, single channel RF transmitters tuned at the factory to one of a number of available channels. Accordingly, operational facilities are forced to carry an inventory having a number of units of each channel, and are unable to change that channel inventory without restocking. Furthermore, because of the increase in antisubmarine warfare activities in recent years combined with the restrictive nature of such sonobuoy inventories, operational facilities are faced with such problems as: (1) the presence of interference caused by using similarly channeled sonobuoys in close proximity to one another; (2) the redundancy caused in coordinated operations by different platforms carrying similarly channeled payloads; and (3) the inability of individual platforms to complete their mission requirements when their predetermined payload will not satisfy changing tactical environments.